Using my little bulldozer, I can build a halfway decent looking fence pretty quick, first taking down all the old wire, then going down the line pulling posts (just weld a hook on the back of the blade to hook a chain to and it's an easy job), and after a few passes to smooth everything out I'm ready to start building the new fence.
For what it's worth, I typically try to build a 5-wire barb wire fence with an offset high-tensile electric wire as my standard fence. Corner posts are 10-12" posts (if I can find them) set as deep as I can set them (typically 4 foot deep).
I'm not sure if I'd even be farming right now if that tornado hadn't ripped through and destroyed so much. Of course, it's much more complicated and involved than that and dealing with all that destruction was pretty devastating at times (I think it was much, much harder on my Grandmother), but things definitely would have been different for me if that tornado hadn't hit the farm.
It's funny how things work out sometimes, and working on that fence, I was wondering where I would be or what I'd be doing if that tornado hadn't went over the farm fifteen years ago.